JS emoji 可以转成base64 的图片格式嘛
例如把 😊 转换成 data:image/png;base64,iVBO...
我现在需要动态修改网页的图标 把一个页面的emoji 放到 网页的图标哪里 但是现在 href里 只能放可访问的地址，如果把emoji换成图片的话 还得存到服务器里，所以想知道能不能直接转成base64
<link rel="shortcut icon" type="image/x-icon" href=“”>
(function () {
var BASE64_MAPPING = [
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
'w', 'x', 'y', 'z', '0', '1', '2', '3',
'4', '5', '6', '7', '8', '9', '+', '/'
];
/**
*ascii convert to binary
*/
var _toBinary = function (ascii) {
var binary = new Array();
while (ascii > 0) {
var b = ascii % 2;
ascii = Math.floor(ascii / 2);
binary.push(b);
}
/*
var len = binary.length;
if(6-len > 0){
for(var i = 6-len ; i > 0 ; --i){
binary.push(0);
}
}*/
binary.reverse();
return binary;
};
/**
*binary convert to decimal
*/
var _toDecimal = function (binary) {
var dec = 0;
var p = 0;
for (var i = binary.length - 1; i >= 0; --i) {
var b = binary[i];
if (b == 1) {
dec += Math.pow(2, p);
}
++p;
}
return dec;
};
/**
*unicode convert to utf-8
*/
var _toUTF8Binary = function (c, binaryArray) {
var mustLen = (8 - (c + 1)) + ((c - 1) * 6);
var fatLen = binaryArray.length;
var diff = mustLen - fatLen;
while (--diff >= 0) {
binaryArray.unshift(0);
}
var binary = [];
var _c = c;
while (--_c >= 0) {
binary.push(1);
}
binary.push(0);
var i = 0, len = 8 - (c + 1);
for (; i < len; ++i) {
binary.push(binaryArray[i]);
}
for (var j = 0; j < c - 1; ++j) {
binary.push(1);
binary.push(0);
var sum = 6;
while (--sum >= 0) {
binary.push(binaryArray[i++]);
}
}
return binary;
};
var __BASE64 = {
/**
*BASE64 Encode
*/
encoder: function (str) {
var base64_Index = [];
var binaryArray = [];
for (var i = 0, len = str.length; i < len; ++i) {
var unicode = str.charCodeAt(i);
var _tmpBinary = _toBinary(unicode);
if (unicode < 0x80) {
var _tmpdiff = 8 - _tmpBinary.length;
while (--_tmpdiff >= 0) {
_tmpBinary.unshift(0);
}
binaryArray = binaryArray.concat(_tmpBinary);
} else if (unicode >= 0x80 && unicode <= 0x7FF) {
binaryArray = binaryArray.concat(_toUTF8Binary(2, _tmpBinary));
} else if (unicode >= 0x800 && unicode <= 0xFFFF) {//UTF-8 3byte
binaryArray = binaryArray.concat(_toUTF8Binary(3, _tmpBinary));
} else if (unicode >= 0x10000 && unicode <= 0x1FFFFF) {//UTF-8 4byte
binaryArray = binaryArray.concat(_toUTF8Binary(4, _tmpBinary));
} else if (unicode >= 0x200000 && unicode <= 0x3FFFFFF) {//UTF-8 5byte
binaryArray = binaryArray.concat(_toUTF8Binary(5, _tmpBinary));
} else if (unicode >= 4000000 && unicode <= 0x7FFFFFFF) {//UTF-8 6byte
binaryArray = binaryArray.concat(_toUTF8Binary(6, _tmpBinary));
}
}
var extra_Zero_Count = 0;
for (var i = 0, len = binaryArray.length; i < len; i += 6) {
var diff = (i + 6) - len;
if (diff == 2) {
extra_Zero_Count = 2;
} else if (diff == 4) {
extra_Zero_Count = 4;
}
//if(extra_Zero_Count > 0){
// len += extra_Zero_Count+1;
//}
var _tmpExtra_Zero_Count = extra_Zero_Count;
while (--_tmpExtra_Zero_Count >= 0) {
binaryArray.push(0);
}
base64_Index.push(_toDecimal(binaryArray.slice(i, i + 6)));
}
var base64 = '';
for (var i = 0, len = base64_Index.length; i < len; ++i) {
base64 += BASE64_MAPPING[base64_Index[i]];
}
for (var i = 0, len = extra_Zero_Count / 2; i < len; ++i) {
base64 += '=';
}
return base64;
},
/**
*BASE64 Decode for UTF-8
*/
decoder: function (_base64Str) {
var _len = _base64Str.length;
var extra_Zero_Count = 0;
/**
*计算在进行BASE64编码的时候，补了几个0
*/
if (_base64Str.charAt(_len - 1) == '=') {
//alert(_base64Str.charAt(_len-1));
//alert(_base64Str.charAt(_len-2));
if (_base64Str.charAt(_len - 2) == '=') {//两个等号说明补了4个0
extra_Zero_Count = 4;
_base64Str = _base64Str.substring(0, _len - 2);
} else {//一个等号说明补了2个0
extra_Zero_Count = 2;
_base64Str = _base64Str.substring(0, _len - 1);
}
}
var binaryArray = [];
for (var i = 0, len = _base64Str.length; i < len; ++i) {
var c = _base64Str.charAt(i);
for (var j = 0, size = BASE64_MAPPING.length; j < size; ++j) {
if (c == BASE64_MAPPING[j]) {
var _tmp = _toBinary(j);
/*不足6位的补0*/
var _tmpLen = _tmp.length;
if (6 - _tmpLen > 0) {
for (var k = 6 - _tmpLen; k > 0; --k) {
_tmp.unshift(0);
}
}
binaryArray = binaryArray.concat(_tmp);
break;
}
}
}
if (extra_Zero_Count > 0) {
binaryArray = binaryArray.slice(0, binaryArray.length - extra_Zero_Count);
}
var unicode = [];
var unicodeBinary = [];
for (var i = 0, len = binaryArray.length; i < len;) {
if (binaryArray[i] == 0) {
unicode = unicode.concat(_toDecimal(binaryArray.slice(i, i + 8)));
i += 8;
} else {
var sum = 0;
while (i < len) {
if (binaryArray[i] == 1) {
++sum;
} else {
break;
}
++i;
}
unicodeBinary = unicodeBinary.concat(binaryArray.slice(i + 1, i + 8 - sum));
i += 8 - sum;
while (sum > 1) {
unicodeBinary = unicodeBinary.concat(binaryArray.slice(i + 2, i + 8));
i += 8;
--sum;
}
unicode = unicode.concat(_toDecimal(unicodeBinary));
unicodeBinary = [];
}
}
return unicode;
}
};
//window.BASE64 = __BASE64;
module.exports = {
CusBASE64: __BASE64
}
})();页面输出如下：
